Additional 10% duty under HTS 9903.04.63 on UK patented pharmaceuticals is reduced to 0% effective July 31, 2026.

CBP has issued guidance implementing a reduction in tariffs on patented pharmaceuticals and associated pharmaceutical ingredients that are products of the United Kingdom under Presidential Proclamation 11020. The Secretary of Commerce’s notice dated July 31, 2026 reduces the additional ad valorem duty rate applicable to these products from 10 percent to 0 percent.

The affected measure is a Chapter 99 provision: HTSUS heading 9903.04.63. This heading applies to patented pharmaceutical articles that are the product of the United Kingdom, as defined in U.S. note 40(c) and (g) to subchapter III. Previously, qualifying imports from the UK under this heading were subject to an additional 10% duty. Effective 12:01 a.m. Eastern Time on July 31, 2026, the additional duty rate under 9903.04.63 is reduced to 0%, eliminating that surcharge.

For customs brokers and trade compliance teams, this is a direct duty calculation change. For any goods entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. ET July 31, 2026, entries that qualify for 9903.04.63 should now reflect a 0% additional duty rate instead of 10%. The base duty rate under the applicable Chapter 1–97 HTSUS classification remains as provided in the tariff schedule; only the additional duty under this Chapter 99 heading is reduced to zero.

Brokers must ensure that products claimed under 9903.04.63 meet the definition of patented pharmaceutical articles of the UK in U.S. note 40(c) and (g) to subchapter III. CSMS #69395344 provides the list of Chapter 1–97 HTSUS classifications that correspond to 9903.04.63 and other Chapter 99 headings established by Proclamation 11020; brokers should use that as a cross-reference to confirm correct pairing of base and Chapter 99 codes.

Operationally, systems used for classification and duty calculation should be updated to reflect the new 0% additional duty rate for HTS 9903.04.63 as of the effective date. For entries filed on or after July 31, 2026, verify that the additional duty is not being assessed. For entries that may have been filed shortly after the effective time with the old 10% rate due to system lag, brokers should consider post-summary corrections or protests, as appropriate, to recover overpaid duties.

This change is specific to UK-origin patented pharmaceuticals and associated ingredients covered by 9903.04.63 and does not alter other Section 232 or trade remedy measures unless explicitly tied to this heading. Questions on Section 232 entry filing can be directed to the Trade Remedy Branch at TradeRemedy@cbp.dhs.gov, but the key compliance requirement is to apply the 0% additional duty rate under 9903.04.63 for qualifying UK products from the stated effective date forward.